Glossary

PRD-driven AI coding

PRD-driven AI coding uses a product requirements document to guide agent planning, story splitting, implementation, and review.

Last updated: May 9, 2026 · Reviewed by ReScience Lab

Why it matters

PRD-driven AI coding gives an agent a product target and gives the developer a source document for review.

What is PRD-driven AI coding?

PRD-driven AI coding means using a product requirements document to guide an AI coding agent from scope to implementation review. The PRD defines the user, behavior, constraints, acceptance criteria, and non-goals before the agent starts changing files.

How it works in practice

A developer writes or generates a PRD, reviews the scope, splits the work into smaller stories, and validates those stories before implementation. The agent then works against a more explicit target than a one-line prompt.

In Hal, the workflow can look like this:

hal plan "describe the product change"
hal convert
hal validate
hal run

Why PRDs help AI agents

AI coding agents are sensitive to ambiguity. If the prompt does not define success, the agent may invent scope or optimize for the wrong outcome. A PRD gives both the agent and the reviewer a shared source of truth.

PRD-driven vs direct prompting

DimensionPRD-driven AI codingDirect agent prompting
ScopeWritten before implementation.Often negotiated during the chat.
ReviewCompared against requirements and criteria.Compared against the latest conversation.
Risk controlEncourages story splitting and validation.Easy to over-broaden.
Best fitProduct changes with behavior and edge cases.Tiny edits or exploratory work.

How Hal uses PRDs

Hal is built around PRD-native coding loops. It helps move from product intent into planned, validated, reviewable work while still requiring a developer to inspect generated output before merging.

Verification rule

Check the current Hal repository, install docs, and release notes before relying on command behavior in production work.

FAQ

Short answers before you put this into an agent workflow.

What is PRD-driven AI coding?

It is using a product requirements document to define scope, constraints, stories, acceptance criteria, and review expectations before an AI coding agent edits files.

Is PRD-driven AI coding only for large features?

No. It is most useful when a change has product behavior, edge cases, or review risk that should be written down before implementation.

Related glossary entries

Keep exploring the pieces of a reviewable coding loop.